This invention relates to an apparatus and method for assembling structures comprising frames and shell plates spreading thereon, like bodies of rolling stock or other vehicles.
Common roof structures of rolling stock comprise a roof framing which consists of carlines 1, stringers 2 and cant rails 3, and roof sheets 4 spreading thereon, as shown in FIG. 1, or a roof framing which consists of carlines 1 and cant rails 3, and roof sheets 4 spreading thereon, as shown in FIG. 2.
Conventional assembling methods for vehicle roof structures thus arranged can be explained as follows:
With the case of roof structures shown in FIG. 1, carlines 1 are placed on positioners previously spaced at given intervals on a jig, clamped with hand vises, and welded to stringers 2, thus making a one-piece roof framing. The integrated roof framing is removed from the jig, turned over with crane or other handling devices, and placed on a stand for welding the back side of the framing to complete the assembly of the roof framing. After roof sheets 4 are placed upside down on a roof-sheet stand, the aforesaid framing is mounted on the roof sheets and tack welded to the sheets into one piece, which is transferred to a welding stand to be secured. Then the framing and roof sheets are spot welded to complete this type of roof structure.
With the case of roof structures shown in FIG. 2, first, cant rails 3 are placed and secured on a jig. Carlines 1 are placed on positioners prespaced on the jig at given intervals, and fastened with hand vises to be welded to cant rails 3. Roof sheets 4 are covered on the integrated framing and brought into a good contact with the carlines 1 while being extended with turn-buckle or other tensioners. Then the roof sheets 4 are tack welded to the carlines 1 in overhead position from under the roof sheets. In tack welding, the roof sheets 4 are manually pressed down from above the sheets with plumbs on to have a complete contact with the carlines 1. When the intermediate assembly has been finished, it is turned over with a crane or other handling devices and mounted on a stand to weld the carlines 1 and roof sheets 4, thus completing this type of roof structure.
Aforesaid conventional method for assembling was associated with such drawbacks as follows:
(a) A roof structure which contains stringers and cant rails as construction members may be easy to turn over and handle as an integrated framing, while a roof structure which consists of only carlines and roof sheets cannot be turned over and handled since only carlines as frame members do not permit a preassembly;
(b) It takes too much time to place and clamp each of many carlines;
(c) Not only does overhead tack welding carlines and roof sheets result in poor welds, but also a two-men operation must be performed, causing extra manpower since at that time the roof sheets must be pressed down to carlines from above to have a good contact between carlines and roof sheets;
(d) Thin-gage sheet metals of which carlines and roof sheets are generally made are likely to be penetrated by welding arc fusion in tack welding, causing poor quality;
(e) Roof sheets must be pulled at five or six places on each side with tensioners for their good contact to carlines, and the tensioning must be made while maintaining the alignment of carlines and roof sheets, thus resulting in labor-intensive and poor operation; and
(f) In turning over roof framings or structures, the use of an overhead crane with slings looped around tends to deform them, and the operation not only takes time with four or five men attending but also is dangerous, giving rise to problems in view of safety. Particularly in the case of roof structures of the type of FIG. 2, carlines are sometimes attached to roof sheets in view of construction and operation, before they are connected with cant rails in vehicle assembling, thus giving rise to difficulties in setting each carline in position on the individual roof sheet.